The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Disk drives for computer systems have a rotating disk and a head that is moved radially over the disk for writing and reading data. The disk is typically divided into a number of concentric, radially spaced servo tracks, and each servo track is divided into a number of data sectors. The disk is accessed a sector at a time by positioning the head over the servo track that contains the desired data sector. As the disk spins, the head creates magnetic transitions in the data sector to record data, or senses previously created transitions to read previously recorded data.
The physical locations of servo tracks and sectors are typically defined by servo segments or sectors that are written at precise locations on the disk during an initialization process. As storage densities increase, it becomes increasingly important that the servo tracks and sectors are positioned very precisely.
Servo sectors can be written to disks during a manufacturing process, using specialized equipment. However, it is more economical to perform “self-servo writing” (SSW), in which the servo tracks are written by the assembled hard disk assembly itself.